Here's my
I have used Frontline Plus on all of my dogs since 1996. I bought BioSpot once (the store clerk said that it was just as good as Frontline and less $$) and used it because I thought that I was going to save lots of $$. BioSpot has the ingredient Permethrin. It can cause seizures &/or death to some dogs. I split 1 vial between my 3 dogs. 2 Yorkies and a Yorkie/Maltese mix. It made an oily spot at the point of application. I didn't like it so I washed it off of the 2 Yorkies first. By the time I got to my Yorkie/Malt to give him a bath he was having seizures. It's not pretty. You know how an insect will twist up when you spray it with bug killer? That's what he was doing. I called my vet at home and he met me at the office, would not speak to me, only took care of my dog. He gave him an iv and some meds to counteract the Permethrin. It was going after his nervous system just like he was an insect. He lived. If I had given him the whole vial he would not have lived. If I had not washed it off of him as soon as I did he would not have lived. If I had not gotten him to the vet as quickly as I did he would not have lived. I learned a big lesson that day. By not doing research properly and only going by saving $$ I could have been the one to kill my own dog. My cost of my ignorance almost was a precious life.
Use whatever you want on your own dogs but to your research first. Ask your vet, call a company, ask here. You'll get alot of different answers, it's up to you to choose wisely.